1. Field of the Invention
The invention relates to a structure and method for manufacturing group III-V composite Schottky. contacts having high-temperature proof, oxidation resistance and low reverse leakage currents.
2. Description of Related Art
As to the prior art, please refer to "Ruthenium and sulphide passivation of GaAs" by S. T. Ali et al, Applied Surface Science 93 (1996) 37-43 and "Electrical Characteristics and Surface Chemistry of P.sub.2 S.sub.5 -Passivated GaAs" by Minorn Sakata et al, Jpn., J. Appl. Phys. Vol. 33(1994) PP. 3813-3824 Contact barriers of Schottky contacts affected by surface state and impurities is mentioned in those papers. Currently, a sulphuration treatment is used to decreased oxidation and defects, thereby efficiently increasing Schottky barriers. However, since a compound formed by sulphur and semiconductor material has a low bonding energy, the sulphur is easily volatilized. In this case, if these devices are put into the environment with air or with higher temperature for a long time, the surfaces of the substrates which have been through the sulphuration treatment appear a high oxidation state resulting in low Schottky barriers. Therefore, the manufactured devices cannot operate under a high temperature for a long time. This problem is desired to be resolved by semiconductor industry.